This invention relates generally to the field of calculators and more particularly to a telescoping hand-held calculator for a special purpose use, such as in the calculating of income taxes and the like.
The accounting profession as well as many scientific disciplines frequently require numerical data or figures based upon calculations from tables of functions or the like. For example, in computing or calculating taxes such as income taxes and the like, it is often necessary to refer to numerous tables and perform a number of independent calculations based upon one or more of these tables to arrive at desired subtotal or total tax figures.
In the income tax field there are as many as eight separate tables of taxes or rates of tax for taxpayers having various statuses. One such table must be used to calculate the taxes on a joint return while a different table is required for those on a single return, head of household return or separate married returns. Similarly, yet further tables must be consulted for the taxes on income of estates and trusts, on corporate income, and for Federal Estate and Gift tax calculations.
While such tables are generally available published in book form, it is nonetheless somewhat inconvenient to refer to such tables. Moreover, a possibility of error is always present as the eye may stray from the desired line in reading one figure from among numerous figures on a printed page.
Various hand-held slide rule-type calculator devices have been proposed in the past for aiding accountants or others in performing such calculations. These devices generally include columns of figures arranged on an insert card to be read through various through-apertures or windows in a cover or receptacle, through which the card bearing the columns of figures is slidably movable. Since these tables are subject to change from time to time, it requires considerable ingenuity to properly arrange all of the necessary columns of figures on a single slidable insert card of reasonable size. More difficult yet is the arrangement of the windows in the cover members in such a calculator to be in registry with the proper figures from suitable lines and columns to obtain the necessary tabular reading in each tax category and at each taxable income figure.